JPH04197854A - Synchronous signal generating device for wiper device - Google Patents

Abstract

PURPOSE:To control wiper blades precisely by fixing a fixing member to a rotating shaft and producing a synchronous signal, composed of the number of pulses set according to reduction ratio, to produce a synchronous signal with shorter width and interval of the pulses. CONSTITUTION:In a wiper device provided with a driver side drive device 16 and a passenger side drive device 18, both of which are controlled synchronously by a control circuit 20, when the rotating shafts of motors are rotated, output shafts are rotated reciprocatedly through worm wheels, sector gears, etc., to swing wiper arms 24, respectively. Then pulses twice the number of teeth of the worm wheel are produced from a hole device 74 by the rotation of a magnet 36 following the rotation of the rotating shaft. Current is conducted from a common contact 68 to a 2nd contact 70 by a cam plate 60. Thus, when an inverter 76 is grounded, a high level of rectangular wave is outputted from the output end of the inverter 76, and when a pulse signal is inputted from the hole device 74, a synchronous signal is outputted from an AND circuit 78.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a synchronization signal generator for a wiper device, and in particular,
The present invention relates to a synchronization signal generating device for a wiper device that generates a synchronization signal for controlling the wiper blades of a wiper device that performs wiping operations on a driver side wiper blade and a parasenger side wiper blade independently so that the wiper blades do not interfere with each other.

[Conventional technology]

2. Description of the Related Art Conventionally, wiper devices have been known in which a wiper blade on a driver side and a wiper blade on a parassenger side perform wiping operations independently. In this wiper device, the rotation of the motor is decelerated by a worm fixed to the rotating shaft of the motor and a worm wheel meshed with the worm, and a link mechanism connected to the worm gear converts the rotational motion into a swinging motion. The wiper arm equipped with a blade is oscillating. In such a wiper device, since both fiber blades perform a wiping operation independently, a synchronization signal for detecting the position of the wiper blade is required to prevent interference between the wiper blades due to out of synchronization. FIG. 6 shows a conventional synchronizing signal generating device, which is attached to the side surface of the worm wheel 10.
It also includes a cam plate 12 having comb-like protrusions formed on its outer periphery. A sliding contact 14 is brought into contact with the comb-like projections of the cam plate 12, and a grounded sliding contact 15 is brought into contact near the comb-like projections of the cam plate 12.

According to this synchronization signal generator, the worm wheel 10
When the cam plate 12 rotates, the sliding contact 14 and the sliding contact 15 are electrically connected by the comb-like protrusions of the cam plate 12, so that a synchronization signal consisting of a pulse train is outputted due to this electrical continuity.

[Problem to be solved by the invention]

However, in the above-mentioned conventional synchronization signal generation device, when trying to generate a synchronization signal consisting of a large number of pulses in order to precisely control the position of the wiper blade, the number of comb-tooth protrusions formed on the outer periphery of the cam plate 12 It is necessary to increase the number of If the number of protrusions is increased in this way, the width of the comb tooth protrusions and the interval between the comb tooth protrusions become narrower, and on the other hand, the sliding contact 14
．． 15 requires an area of a predetermined size, so there is a restriction on the pulse width of the synchronization signal to be generated, and it is not possible to output a synchronization signal consisting of a large number of pulses.
There is a problem. Furthermore, increasing the number of comb tooth projections also increases manufacturing costs.

The present invention has been made to solve the above-mentioned problems, and is for a wiper device capable of outputting a synchronized signal consisting of a large number of pulses with a constant pulse width and narrow pulse intervals to precisely control the position of the wiper blade. An object of the present invention is to provide a synchronization signal generator.

[A means of promise to solve problems]

In order to achieve the above object, the present invention provides a deceleration mechanism including a plurality of gears and for decelerating the rotation of a rotating shaft of a motor and transmitting the reduced rotation to a driven shaft connected to a wiper arm; A rotating member fixed to the rotating shaft of the motor so as to rotate, a pulse signal generating means for generating a pulse signal as the rotating member rotates, and a cam plate provided on a driven shaft side gear of the speed reduction mechanism. and a contact element that contacts the cam plate, and a signal output means for outputting a signal that reaches a predetermined level in a predetermined rotation angle range of the driven shaft side gear, and when the signal is output from the signal output means. and a logic circuit for passing the pulse signal outputted from the pulse signal generating means as a synchronization signal.

[Effect]

The deceleration mechanism of the present invention includes a plurality of gears, decelerates the rotation of a rotating shaft of a motor, and transmits the reduced rotation to a driven shaft connected to a wiper arm. A rotating member is fixed to the rotating shaft of this motor so as to rotate together with the rotating shaft of the motor.

Furthermore, a pulse signal generating means is provided that generates a pulse signal as the rotating member rotates. The gear on the driven shaft side of the speed reduction mechanism includes a cam plate and a contactor that contacts the cam plate, and is provided with a signal output means for outputting a signal that reaches a predetermined level within a predetermined rotation angle range of the gear on the driven shaft side. There is. The logic circuit passes the pulse signal output from the pulse signal generation means as a synchronization signal when the signal is output from the signal output means. Since the driving shaft of the speed reduction mechanism rotates many times during one rotation of the gear on the driven shaft side, in the present invention, a rotating member is fixed to the rotating shaft of the motor, that is, the driving shaft of the speed reducing mechanism, and the rotation of this rotating member is controlled. By generating a pulse signal in conjunction with this, it is possible to generate a synchronization signal consisting of a large number of pulses. When a single helical worm and a worm wheel with m teeth are used as the speed reduction mechanism of the present invention, the worm rotates m while the worm wheel rotates once, so the number of teeth is determined according to the number of teeth of the worm wheel. That is, it is possible to generate a synchronization signal consisting of a number of pulses corresponding to the reduction ratio.

Therefore, the pulse width and pulse interval of the synchronizing signal can be narrowed without narrowing the width of the comb tooth protrusions as in the conventional case. Note that by increasing at least one of the number of gear teeth and the number of fixed members on the driven shaft side of the speed reduction mechanism, a synchronization signal with a narrower pulse width and pulse interval can be generated.

〔Effect of the invention〕

As explained above, according to the present invention, the fixed member is fixed to the rotating shaft of the motor to generate a synchronization signal consisting of a number of pulses corresponding to the reduction ratio, so that the width of the comb tooth protrusions can be narrowed. Therefore, it is possible to generate a synchronization signal with a narrow pulse width and pulse interval, thereby achieving the effect that a synchronization signal that can precisely control the position of the wiper blade can be generated at low cost.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings. FIG. 2 schematically shows the wiper device of this embodiment, and this wiper device includes a driver-side drive device 16 and a pan sensor-side drive device 18, each of which is equipped with a motor. The driver side drive device 16 and the pan sensor side drive device 18 each have a wiper blade 22 at one end.
The other end of the wiper arm 24 is connected to the wiper arm 24. Driver side drive device 16 and pan sensor side drive device 18
is connected to the control circuit 2G to supply a synchronization signal,
The control circuit 20 is connected to control each motor of the driver side drive device 16 and the pan sensor side drive device 18. Further, a wiper switch 26 and an ignition switch 28 for turning on and off the wiper device are connected to the control circuit 20.

Next, the driver side drive device 16 and the pan sensor side drive device 18 will be explained in detail. Note that since the driver side drive device 16 and the pan sensor side drive device 18 have the same configuration, only the driver side drive device 16 will be described below, and the description of the pan sensor side drive device 18 will be omitted.

FIG. 3(1) shows a cross-sectional view of the driver side drive device 16, and a commutator is installed in the first casing 30 so that the rotating shaft 38 protrudes from the opening side of the first casing 30. A motor 32 having a motor 34 is housed therein. A two-pole magnet 36 formed in a ring shape is fixed to the rotation shaft 38 on the side of the comic data 34 so as to surround the rotation shaft 38 (FIG. 3 (2)). A Hall element 74 is disposed near the magnet 36 so as to face the outer periphery of the magnet 36 . Further, a single spiral worm 40 is fixed to the distal end side of the rotating shaft 38.

A worm wheel 44 having m teeth and meshing with the worm 40 is rotatably housed in the second casing 42 combined with the first casing 30 . An eccentric shaft 46 is fixed to one surface of the worm wheel 44 at a position eccentric from the rotation center of the worm wheel 44. The eccentric shaft 46 rotatably supports the other end of a first link 50 having a sector gear 48 formed at one end thereof.

A pin 52 is fixed to the center of the sector gear 48. One end of a second link 54 is rotatably supported by this pin 52 . Further, a fan-shaped gear 56 that meshes with the fan-shaped gear 48 is provided.

An output shaft 58 is fixed to the center of the sector gear 56, and the output shaft 58 is rotatably supported by the second casing 42 such that one end thereof protrudes from the second casing 42. The output shaft 58 rotatably supports the other end of the second link 54 . In addition, this output shaft 5
A wiper arm (not shown) is connected to the distal end of 8.

As shown in FIG. 4, a cam plate 60 made of a conductive member is fixed to the other surface of the worm wheel 44 along the circumferential direction of the worm wheel 44. As shown in FIG. A reversing protrusion 64 and a stop protrusion 66, which protrude in the direction of the rotation axis, are formed on the cam brake 60 at positions facing each other across the rotation axis of the worm wheel 44. Both end portions of the cam plate 60 in the circumferential direction are opposed to each other at a predetermined distance apart, and a cutout portion 62 is formed in the center portion of the cam plate 60 in the circumferential direction, and the width thereof is narrower than that of the other portions.

A first contact 72 is provided at a position where it can contact the reversing protrusion 64 and the stop protrusion 66, and a second contact 70 is provided at a position where it can contact the portion exposed by the notch 62 of the worm wheel 44. the first part of the cam plate 60
Is it grounded at a position where it can contact the intermediate portion between the contact 72 and the second contact 70? Three common contacts 68 are arranged.

As shown in FIG. 1, the Hall element 74 is connected to the AND circuit 78.
The second contact 70 is connected to the other input terminal of an AND circuit 78 via an inverter T6.

The operation of this embodiment will be explained below. When the rotating shaft 38 of the motor rotates, the output shaft 58 is reciprocated within a predetermined angle range via the worm 40, worm wheel 44, first link 50, sector gear 48, and sector gear 56, thereby causing the wiper arm 24 to swing. be moved. Since the two-pole magnet 36 rotates as the rotating shaft 38 rotates, twice the number m of teeth of the worm wheel 44, that is, 2 m pulses are generated from the Hall element 74 during one rotation of the worm wheel 44. Ru. When the common contact 68 and the second contact 70 are electrically connected by the cam plate 60 as the worm wheel 44 rotates, the input end of the inverter 76 is connected to the second contact 70, the cam plate 60, and the common contact. 6
As shown in FIG. 5, since the common contact 68 and the second contact 70 are connected to each other from the output terminal 60, a rectangular wave that is at a high level is generated as shown in FIG. is output. Since the pulse signal output from the Hall element 74 is input to one input terminal of the AND circuit 78, the pulse signal output from the AND circuit 78 is outputted from the output terminal of the AND circuit 78 while the output of the inverter 76 is at the noise level. : The pulse signal shown in 2 is output as a synchronization signal. By counting the number of pulses of this synchronization signal, the wiper blade 2
2 is detected, and the driver side drive device 16 and the parasenger side drive device 18 are moved so that the driver side wiper blade and the parasenger side wiper blade do not interfere with each other.
are controlled respectively.

Note that when the first contact 72 contacts the reversing protrusion 64, a signal indicating the reverse position of the wiper blade is output, and when the first contact 72 contacts the stop protrusion 66, a signal indicating the stop position of the wiper blade is output. be done.

In the above, a two-pole magnet and a worm wheel with m teeth were used, but by increasing the number of poles of the magnet or the number of teeth of the worm wheel, the synchronization signal pulses generated per revolution of the worm wheel The width and pulse spacing can be further reduced. By narrowing the pulse width and pulse interval of the pulse signal in this manner, the position of the wiper blade can be controlled more precisely.

In the above, a Hall element was used to output the pulse signal, but a magnetic detection element (magneto-resistance element) such as a reed switch may be used to output the pulse signal, or a gear-shaped magnetic sensor may be used instead of a magnet. In addition to using a rotor made of a body, an electromagnetic pickup equipped with a detection coil may be used instead of the Hall element. Further, although a speed reduction mechanism consisting of a worm and a worm wheel is used, a speed reduction mechanism consisting of a gear train, a helical gear, etc. may also be used. moreover,
Although a logic circuit consisting of an inverter and an AND circuit is used, it may be constructed using a combination of other logic elements. In addition, in this example, rotation was detected using magnetism and a pulse signal was output, but a disc with a slit was placed at the same position as the magnet, rotation was detected using a photointerrupter, etc., and pulses were output. You may.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of an embodiment of the present invention, FIG. 2 is a schematic diagram of a wiper device of the present invention, FIG. 3 (1) is a sectional view of the driver side drive device of the above embodiment, and FIG. ) is a sectional view taken along the line A-A in FIG. 3 (1), FIG. 4 is a plan view of the cam plate portion of the above embodiment, FIG. 5 is a waveform diagram of each part of FIG. 1, and FIG. 6 is a diagram of the conventional It is a top view of a cam plate. 36... Magnet, 38... Rotating shaft, 40... Worm, 44... Worm wheel, 74... Hall element, 78... AND circuit. 36. Magnet 44- Warm nail 78-7 Note turn 8 Figure 4 Figure 1

Claims (1)

[Claims] (1) A deceleration mechanism that includes a plurality of gears and that decelerates the rotation of the rotating shaft of the motor and transmits the reduced rotation to a driven shaft that is connected to the wiper arm, and a rotating shaft of the motor that rotates together with the rotating shaft of the motor. a rotating member fixed to the rotating member, a pulse signal generating means for generating a pulse signal as the rotating member rotates, a cam plate provided on the driven shaft side gear of the speed reduction mechanism, and a contactor that contacts the cam plate. and,
A signal output means for outputting a signal having a predetermined level within a predetermined rotation angle range of the driven shaft side gear; and a pulse signal output from the pulse signal generation means when the signal is output from the signal output means. A synchronizing signal generator for a wiper device, including a logic circuit that passes the signal.